Grinding machine



June 16, 1953 R. GQKIRBY GRINDING MACHINE 8 Sheets-Sheet 1 Filed Jan. 21, 1950 IN VEN TOR.

ROY 61 K #75) xmmvfl/ 4 T TORNEYS June 16, 1953 M KIRBY 2,641,874

' camnmg; MACHINE FiledlJan. 21', 1950 o 8 Sheets-Sheet 2 INVENTOR.

. ROY 67 K/REY immwzxw June 16, 1953 R. s. K'liQBY 2,641,874

GRINDING MACHINE Filed Jan. 21, 1950 8 Sheets-Sheet 3 4 O v49 0 U AMA-L? 0 0 O L e m;

i E/ lllllllllllllllllllllHlIl INVENTOR.

June 16, 1953 R. a. KIRBY GRINDING MACHINE 8 Sheets-Sheet 4 Filed Jan. 21, 1950.

INVENTOR ROY 6 K/RBY BY 11.14 m wry/W A T TORNEYS June 16, 1953 R. Q, KlRBY 2,641,874

GRINDING MACHINE Filed Jan. 21, 1950 8 Sheets-Sheet 8 I INVENTOR.

//9 ROY a. Kl/PBY imazamyzz'w ATTORNEYS Patented June 16, 1953 I ,1

GRINDING MACHINE Roy G. Kirby, Cincinnati, Ohio, assignor to The Cincinnati Milling Machine 00., Cincinnati, Ohio, a corporation of Ohio Application'January 21, 1950', Serial No. 139,815

1 This invention relates to improvements in grinding machines and has reference to a machine particularly adapted for production by grinding of cam or other surfaces of irregular or noncircular contour.

One of the objects of the present invention is the provision of a machine of this character which .will effect a uniform grinding action on surfaces of irregular contour and will eliminate chatter or vibratory effects due to the rise and fall action or relative movement of the work and grinding wheel during generation of the contour.

A further object of the present invention is the provision in connection with a machine of this character of means for effecting an automatic control of the rate of rotation of the work piece in accordance with the variations in its configuration.

An additional object of the invention is the provision of a machine which may be employed both to produce the guiding cam r cams for work piece reproduction from either a prefinished work piece or a simple pattern in which the guide cam or cams so produced may be then utilized without change of position for commercial production of duplicate work pieces and inwhieh multiple angularly related guide cam-s may be readily produced as a unitary element by utilization of a single pattern element.

It is additionally thepurpose of this invention to provide a machine for cam grinding purposes which will permit of ready interchange of various pattern sets, of relative angular adjustment of the Work piece and pattern as desired and of supporting means for the machine elements which will be so constructed and related as to minimize the inaccuracies due to unbalance or twisting strains resultingfrom the grinding action and the controlling action of relative movement of the parts.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification, considered in conjunction with the accompanying drawings forming a part thereof, and it is to be understood that any modifications may be made in the exact structural details there shown and described, within the scope of the appended claims, without departing from or exceeding the spirit of the invention.

Figure l is a perspective view of a machine embodying one form of the invention.

Figure 2 is a plan view of the headstock porthe machine as shown in Figure 2,

' 'lClaims. (Cl. 51--101)' Figure 4 is a view partially in elevation and partially in section as on the line 44 of Figure 2.

Figure 5 is a view similar to Figure 4 as on the line 55of Figure 2. 'r r Figure 6 is a fragmentary longitudinal sectional view as on the line 6-6of Figure 2.

Figure? is a plan view of the tailstock portion of the machine.

Figure 8 is a longitudinal section of the tailstock and mounting on the line 8-8 of Figure 7.

Figure 9 is an end View of the swinging carriage and associate parts.

Figure 10 is a fragmentary sectional view as on the line I0l0 of Figure 8.

Figure 11 is a diagrammatic view illustrating the utilization of the invention in formation of a master cam.

Figure 12 is a similar view illustrating workpiece production by a utilization of the cam as generated in Figure 11. v

Figure 13 is a diagrammatic view of a master cam peripheral speed controlling device utilizcated in Figure 1.

able in connection with thepresent invention.

Figure 14 is a section of a modified form of carriage control spring mounting.

Figure 15 is a longitudinal section of the rate valve.

Figure 16 is a diagrammatic view of an auto- .matic electrical work speed control.

In the drawings, the numera1 20 designates the bed of a cylindrical grinder which may be of standard commercial type provided with the re- .ciprocating table 2| and the wheelhead carriage This latter motor is connected by belt 21 to drive,

spindle 28 of a second smaller grinding wheel 29. This wheel-and its associate parts are supported in bracket hinged as at 3| to the wheelhead so that the parts may be swung downward to bring the grinding wheel 29 into grinding position with respect to a work piece as is indi- Alternatively, the bracket and grinding wheel may be swung upward toward the motor 24 when out of grinding position so that desired grinding operations may be performed. As has been mentioned, the present invention is particularly adapted for use in the production or generation by grinding of cams or like elements and in the accomplishment of this usually special work holding mechanism is provided. In its primary form this mechanism includes a heavy bracket or bed plate 32 of appreciable longitudinal extent which is bolted or suitably secured in position on the table 2| of the grinding machine and serves as a support for V the work holding, work driving, and work position determining mechanisms which are thus movable or translatable as an entirety with the table and with respect to the position of the grinding wheels. Supported by the bed plate .32 is a longitudinally extending rock shaft or spindle 33 supported at various points intermediate its length as by anti-friction bearings 34, 35, and 35 as indicated in Figures; 6 and 9. This shaft is provided with the flats as at 40 providing substantially V-shaped configuration to facilitate ready clamping in position thereon for rotation therewith the oscillating bracket mem relation to the bearing unit, these members being connected at their outer ends-by the swivel blocking'rod 5! which may be put under tension by tightening of screw 58, drawing the clamping arms angularly inward so that the lugs 52 and 54 will exert suitable retaining pressure against the bearing holding it in position on the lugs 45 and 46. Similar structure is provided in connection with the bracket 42 in which the bearing unit 59 for the headstock spindle 60 is seated against the portion SI of the bracket arm, use being made of the clamps 62 and 63 connecting clamp rod 64 and nut 65.

It will be evident that byloosening of the nuts 58 and 65, the rods 5'! and 64 may be swung outwardly into disengaging relation to the clamp arms which may then be opened, releasing the bearings and the unit assembly readily removed.

The shaft 49 carries on its outer or left hand end as particularly illustrated in Figure 6 the driving pulley or sheave fifi'rotatable by belt 61 of the table pulleyBS rotatably supported by the rock shaft 33. This pulley is, in turn, driven through .belt 69 and pulley ID on the shaft of the rotary head-stock operating hydraulic motor II which thus supplies power for rotation of the work. Carried by the shaft 49 is the rotary head 12 which is of larger diameter than the bearing unit4'I. The outer face of the head I2 therefore forms a seat to receive the cam cluster 01' like member I3 which may constitute either the work piece to be ground or the guiding form to control the workpiece produced during different phases of operationof the machine. In any event, the member 13 has an internal bore of size to slip over the bearing unit and closely 'interfit with the member I2 where it is retained between the clamp nut element I4 and the flange 15. A key or spline as indicated at '16 perfectly locks the parts for synchronous rotation.

Integral with the spindle 49 is the bushing I1 having a tapered recess to receive the headstock center 60, while intermediate the flange I2 and the portion I! the spindle 49 is threaded as at I8 to receive clamp nut 19 tightening the bearing clamping collar 80.

.4 A bearing clamping collar 8| circumscribes the inner portion of member 11 for securing the outer elements of the double taper roller bearing in position within the bearing sleeve or support 59. Secured to the face of the member 8| as by the clamp bolts 82 is the retaining collar 83 interengaged with the shoulder on the member IT for looking it in position against endwise movement with respect to the bearing assembly. The member TI terminates in a reduced shoulder portion at 84 centralizing the collar 85 retained on the inner face of H by bolts such as 86. This collar has an arcuately extending T slot as at 8'! receiving T bolt 88', permitting limited oscillatory movement. of disc 89 carrying the headstock drive bracket 90. The member 85 is provided with graduations as at 9| for cooperation with the indicator or pointer 92 on member 89 minutely to indicate the exact angular relative adjustment of said parts and thus. the, phase. relationship between the position of the member I3 as determined by key I6 and the position of the drive bracket It will be understood the drive bracket 90 by engagement with driving dog 93'on the work piece. 94., thus definitely determines and establishes the phase angle relationship between the work piece and the member l3. This relationship having been established, tightening of clamp nut 95 rigidly locks the parts 85 and 89 in their desired angular or phase adjusted position.

For support of the opposite end of the work piece 94, there is provided a tailstock mechanism particularly illustrated in Figures '7 and 9, which mechanism is carried by the bracket 43 supported by the rock shaft 33. The bracket 43 is provided with ways as at 96 and 91 for the tailstock unit 98 which includes sleeve 99 within which is slidably mounted the telescoping sleeve or bushing I 00 tapered to receive the ta'ilstock center In I. A pin I02 engaged in the groove I83 of bushing I08 guides same for longitudinal movement. The projection of the tailstock center is effected by spring I04 bearing against the collar I05 interiorly pinned to the sleeve I00 and which, in turn, guides the adjusting screw I98 engaging nut I07 keyed at I08 to the sleeve I99. This nut serves to vary the compression of spring I89 which bears against washer IIO- seated in the sleeve I08. Rotation of the screw is eifectable by the hand wheel I II. For ordinary retraction of the tail-- stock center IIII to release the work, use is made of the customary control handle II2 pivoted to member 98.

In the utilization of the present invention for the production of master control cam units or the like, a pattern, model, or work piece H4 is clamped in position between the headstock and tailstock centers as indicated in Figure 1. The swinging bracket 22' carryin the grinding wheel 29 is lowered in the position indicated in'Figure 1 and one of the cam or contour surfaces I I5 of the work to be reproduced is engaged with the abutment lug I I6 carried by a'standard I I I which has a dovetail guideway at '8 interfitting with the dovetail guide II9 upstanding from the rear portion of the member 32. This mounting of the standard is such that it might be readily aligned with any one of the several cam or eccentric elements I I5 on the member I I4. To retain the parts in suitable interengaging relation while allowing of oscillation of the shaft 33 and parts supported thereby during grinding, the standard preferably supports a bracket I20 to which is secured spring I2I having its outward end extending forwardly and supported from the member I22 carried by the upper portion of the oscillating carriage or frame I23. In Figure 1 the structure shown is particularly adapted for short work in that the member I22 is indicated, as rigidly mounted on I23 while in Figure 14 it has been shown as carried by a hook clamp or attachment I24, permitting of its sliding along the frame to insure'a most direct line pull of the spring between the support elements I20 and I22. An attaching screw I25 and adjusting nut I28 in either event permits proper determination of the acting spring forces which, as will be most evident by reference to Figure 14, causes an upward and inward clockwise oscillatory urge of the frame and pattern member I 'With the parts thus positioned, the unit indicated at 13 comprises the workpiece, and an element thereon to be formed is properly aligned with the grinding wheel 29 which preferably has a surface corresponding in'arcuate dimension to the rounded contacts I2! on the abutment I I6.

Rotation of spindle 49 will revolve a selected section, such as I 28 of the work piece, to present all portions of the periphery thereof to the active surface of the grindingwheel 29.. At the same time, the synchronized rotation of member II4 by contact of H5 with the fixed abutment II6- I21'will cause an in and out oscillation of the entire oscillatory carriage, such that the contour of the portion II5 will be reproduced with ex treme accuracy on the member I28.

If it is desired to produce a series of master cams, such as I28,'on the element designated as an entirety by the reference character I3 but in angularly phased relation, as for example, the relationship existing between the various cams on an automobile cam, this result may be efiected, if desired, by utilization of a single pattern element and without adjustment of the position of the springsupports II I and I24.

In accomplishment of this result, after the first member I28 has been completed, nut 95 may. be loosened and collar 89 may be given an angular rotation of desired amount as easily determinable by relationship of scale 9| and pointer 92 according to the relative out of phase or angle between corresponding configurations desired of the cams to be produced, the parts located, and the grinding wheel 29 aligned with the portion of member I3 on which the next cam surface is to be generated or produced and this operation continued until all such cams have been formed from the single pattern and in desired angular relationship one to the other.

As an alternative, of course, and as particularly indicated in connection with Figure l, a complete pattern or a sample work piece may be inserted at H4, in which event it is unnecessary between grindings of the elements I28 to make any change in phaserelationship between pattern and work but each element ofthe work being ground will be a direct reproduction of the particular pattern.

At the completion of such a work piece forming operation, downward oscillationzof the control handle I29 will rock and lock the oscillat ing carriage in a retractedposition as indicated by the dotted lines in Figure 5. When so positioned, the table is preferably translated to move the parts out of alignment with the main grinding wheel head, after which the bracket 22 is swung into its upward or retracted position when the machine is conditioned for operation of the main grinding wheel 23.

'The base of the unit 32 is provided with a guide portion or waysat I3I to receive a bed plate I32 adjustably retained in position by bolts I33 engaged in the slots I34 permitting of a forward and back adjustment of the position of the bed plate I32 as determinable by the scale I33 and index I34. A screw I35 swiveled to the base '32 and engaging the bracket nut I36 on the plate I32 may be utilized, if desired, for accurately effecting this adjustment.

The plate I32 has rising therefrom the pair of brackets or standards I31 mounting at their upper portion the shaft I38 and near their bases the rods I39 and I40. Rod I39 extends to the left of the unit, as viewed in Figure 2, and has secured to its projecting end the block I4I carrying rack I42 meshing with pinion I43 for effecting longitudinal sliding of the rod. The pinion I43 is mentioned on the shaft I44 extending forwardly through plate I45 carried by the base plate 32 and is provided with the actuating handle means I45. The plate itself is formed with sockets I41 with which the locking pin I48 of the handle may be selectively engaged to lock the handle and thus the pinion and rack in desired adjusted position. A pointer I49 movable with the handle cooperates with indicia I50 on plate I45 to denote the particular adjustment effected by movement'of the handle.

' 7 While the rod I40 may also, be movable with the block, it is preferably fixed in position with the standards and therefore forms a guide both for the sliding movement of the block with the plate I5! which is likewise mounted on rod I39. Member I5I is split, as at I52, the furcations thus provided spanning the rod I39 and may be clamped in adjusted position along the rod by screw I53. Member I5I is provided with dovetail rib I54 extending parallel to the rods I39 and I40 and adjustably mounting the uprights I55 which have yoke portions spanning the shaft I38. Mounted on the shaft I38 is the hub I56 carrying a'guide roller I57 which is thus supported for rotation on the shaft I38 and for translation with rod I 39 as it is reciprocated. By reference particularly to Figure 2, it will be noted that this guide roller I5? is adapted to be positioned for peripheral running engagement with the discs or cam elements I28 and that by outward rocking of the oscillatory carriage, as by actuation of lever I29 retracting the members I28 from'interengagement with the member I52 and suitable actuation of handle I45 the mem- 'ber I52 may be brought into alignment with any selected member I28. The spacing of the sockets I41 on plate I45 may be so positioned that each movement of the handle from one socket to the next willeffect the exact accurate translatory adjustment of the member I52, it being understood that if a different series of positionings due, to different spacing of members I23 is desired that a new plate I45 may be substituted or that a sufficient number of sockets may be provided to take care of the desired incremental shifting movements. e

In the diagrammatic view, Figure 11, the oscillation of the swinging carriage is shown as controlled by interengagement of the pattern element II5 with the abutment I2'I, parts being urged toward each other by the spring IZI. At this time, the small grinding wheel 29 is being employed to generate the master cam elements such as I 28. When, however, the master cam has been generated and is then being utilized for production of th work piece I58 or a series of similar work pieces, the wheel 29 is no longer employed but in its stead the large grinding wheel 23, as diagrammatically illustrated in Figure 12. Under these conditions the oscillatory control is by interengagement' of the rotating ,disc' or roller I51 and the appropriate previously gener ated cam element I28. In order that the oscillatory movement in this work piece production may be identical with the oscillation imparted by the pattern during generation of the cam, it is preferable that this guide wheel I51 be identical in diameter with the diameter of the wheel 29 employed for the generating operation.

During this phase of utilization of the machine, the spring I2! and its supporting bracket II1 are removed so that the table may be transmitted to bring the grinding wheel 23 in proper engagement with the portion of the work piece to be ground and without interference from the bracket I1. As it is still desired that the carriage oscillation be controlled by spring again, the bed plate 32 is provided with a standard I69 which is connected by bolt ISI, the actuating spring I62 definitely connected by screw I63 and adjusting nut I64 with a second standard or bracket I65 mounted on the oscillating carriage unit. The spring thus continuously urges and holds the pattern element I28 being employed in yielding contact with guide disc I51 to permit the necessary in and out swinging of the carriage while maintaining sufiicient pressure properly and adequately to maintain the work in engagement with the grinding wheel.

Reference has been made to the fact that the cam and work piece assembly are rotated as by the hydraulic motor 1I through suitable belting and the speed reducer I65. If the amount of irregularity of the cam or eccentric surfaces being produced is but slight it is possible to perform the grinding operation by continuous speed rtation of the parts.- For best grinding results, however, as to finish and accuracy the present invention contemplates automatic modification of the rate of drive of the work pieces in accordance with variations in configuration so that there is a substantially uniform relative surface speed between the operative phase of the grinding wheel and the work piece and a suitable slowing down of the rate of rotation of the Work piece in accordance with increase in radius and a corresponding relative speeding up of rotation as the work piece radius decreases.

One mechanism for accomplishment of this result is particularly illustrated in connection with Figures 3 and 4 of the drawings. Secured to the oscillating carriage at the left hand end thereof is a plate I 12 having an arcuate rack portion I13 concentric with the shaft 33 about which the carriage oscillates Thi rack meshes with pinion I14 carried by spindle I15 journaled in the bearing I15 carride by the bed plate 32 and has splined thereon the sliding clutch I11 outwardly urged by spring I18. Axially aligned with the spindle I15 is the valve stem I19 journaled in the valve block or casing. I88. Connected into the casing I88 is exhaust conduit I8I leading from the hydraulic headstock drive motor 1I, this motor also being coupled to a pump unit by conduit 288 or source of actuating medium as at I82.

The pressure medium from the motor discharges by way of the annular groove I83.of the bushing I84 in the valve block and conduit 2IlI to the pump unit I82 for reutilization. The bushing is provided with a throttle aperture, preferably of the V-type, at I85 variably con- 8. trolled by the relative positioning with respect thereto of the slot I86 in the valve stem. The stem itself is provided with a longitudinally extending bore I88 communicating with groove I99 which is, in turn, coupled by conduit I8I with the discharge side of the hydraulic motor 1|. It will be evident that depending upon the rotary adjustment given to valve stem I19 a variable amount of actuating fluid will be allowed to exhaust from the driving pump H and thus the rate of actuating of the headstock spindle 49 by way of the speed reducer I66 and the belts 61, 69 is accurately controlled. Due to the clutch connection between the members I11 and I19 the valve stem may be independently rotated with respect to pinion I14 for selection of any desired rate of headstock actuation for a particular positioning of the pinion. During grinding operations, whether for production of the cam elements I28 through use of the grinding wheel 29 or for production of the eccentrics or cams such as II5 through use of the wheel 23, there will be a corresponding in and out oscillatory movement of the work supporting carriage. This movement will be transmitted through rack I13 to the pinion I14 and thus to the valve. As the carriage swings inward or toward the grinding wheel, shortening the work radius, the pinion will be rotated in a clockwise direction to open up the eifective control porting in the valve chamber, proportionally increasing the rate of rotation imparted to the work and control cams. However, as the carriage is oscillated outwardly or in a clockwise direction, the pinion will thereby be rotated in a counterclockwise manner, closin down the throttling action and slowing up rotation of the work. It has been found by utilization of this mechanism that a much better and more accurate finish with the absence of chatter effects can be produced as, for example, on the high points of automobile camshafts, and it is possible with uniform rotation irrespective of the particular radius of the work being presented in opposition to the grinding wheel.

An alternative form of control for accomplishment of this result has been indicated in Figure I3. In this view the disc or roller I51 which engages the members I28 has been indicated as keyed or rigidly mounted on the shaft I38, which projects outwardly from the shaft support and is provided with the pulley 202 connected by belt 283 with a second pulley 284 on the sleeve nut 285. This nut is supported on the threaded portion 206 with shaft 201 which is driven by the variable speed motor 208 provided with a suitable controller 289 for determining the speed of operation of the motor. As in the form of the invention previously described, the headstock is basically driven by the hydraulic motor 1I supplied with actuating fluid from a pump or hydraulic unit I82 while the discharge from the motor leads into the valve block 2I0 containing a valve corresponding in function and operation to the valve mechanism contained within valve block I 88. The position of this valve is determined by rod 2I I pivoted to one end of lever 2I2 intermediately pivoted supported at 2I3 and terminally pivotally connected by the link 2I4 to the sleeve nut 285. In operation, controller 289 is set to select a proper non-chatter producing speed of rotation for the headstock and the headstock motor is put in operation through activation of the pump or unit I82. The frictional engagement between the elements I 28 and I51 will effect rotation of the member I51 at a surface speed corresponding to the surface speed effected by rotary movement of member I28.

It will, therefore, be evident that as the radius of curvature of member I28 increases it will tend to speed up the rate of rotation of I51, 202, which action will advance the nut along the screw 206, thus transmitting motionto valve rod 2 moving the valve to a throttle or slow downthe motor until the rate of advance of the work surface has been reduced to the preselected rate of operation determined by motor 208 so that the nut and screw rotate in synchronism without relative longitudinal movement. correspondingly, a reduction in radius will cause offset direction of relative movement of the screw and nut,

' speeding up the work rotation until the prescribed surface speed is reached andmaintained.

It will thus be noted that inboth of the forms of the invention here chosen for purposes of illustration, means have been provided for automatically varying therate ofrotation imparted to the work'during grinding in accordance with the variations in configuration of the workso that'proper control of surface speed to insure InFigure 16 there has been diagrammatically illustrated an automatically controlled electrical 10 tern in engagement with a shoe having a large radius, grinding the control cam with by a g erating wheel of lesser radius than'that of the shoe, supporting the ground control cam in. engagement with a shoe of substantially the same radius, grinding the control cam with a gentuting a work piece for the original pattern in corresponding axial relationship to the control cam, and grinding the work piece to a cam contour determined by interengagement of the control cam and said shoe.

2. A cam grinding attachment for. grinding machines which embody a base, a work table, a grinding wheel support and means for effecting relative translatory and feeding movements of the work table and grinding wheel support with respect to the base, said attachment including a base plate adapted to be mounted on the table, a carriage supported by the base plate for oscillation with respect thereto, a headstock unit mounted on the carriage, variable speed driving means for eifectingrotation of the headstock unit, and control means effective during oscillation of the carriage to vary the rate of rotation imparted to the headstock by said driving means, saidmeans including a rotarycontroller and connections between the carriage and controller 'actuable by.

oscillatory movement of the carriage for effecting speed varying rotation thereof upon oscillating movement of the carriage. I

3. A cam grinding machine including. a support, a carriage mounted thereon forv oscillation with respect thereto, a work driving headstock supported on the carriage for oscillation theredrive in place of hydraulic for the headstock and v cam members. In this View the numeral 2 designates a variable speed member which, through the speed reduction element 266, operates pulley 210 and, in turn, through belt 269 drives the regular pulley 68 of the machineand thus by belt 61,

the sheave or pulley 66 on the headstock spindle 25, these latter parts being shown in detail, for example, in Figure 6 of the drawings. As in the form previously described, the oscillation of the headstock carried through rack I13 rotates pinion H4 carried by spindle I15. In the present in-= stance, however, in place of the spindle being coupled by the adjustable clutch device [17 with thevalve I30 the coupling is to the rotary arm '27? of the rheostat or like variable resistance member 213. This member is coupled by line 274 with the motor 21! and additionally with power line, such as 2'15 at the opposite power circuit line 216, being coupled with the motor 21 [in conventional manner.

With this form of construction any oscillatory or partial rotary movement imparted to the p nion I'M by carriage effected movement of the rack H3 will vary the position of the control arm 212 automatically to vary the rate of rotation of the shaft 211 of motor 2' and thus the rate of drive of the headstock. In this instance also we have,

, as before, means controlled by the guide cam for with, said headstock having a pattern cam receiving portion adapted to receive a pattern cam having axially spaced control cam portions, guides mounted on the support, a slide carried by said guides, bracket means rising from the slides,

a contact shoe rotatably supported by the brackets and shiftable by the slide selectively to engage different effective portions of a pattern cam on the headstock for peripheral frictional engagement therewith, driving means for rotating the headstock, a rate controller for said driving means, and operating connections between said shoe and rate controller variably to determine the rate of drive of the headstock in accordance With the peripheral speed frictionally imparted by the headstock driven cam to the rotatable contact shoe.

4. A cam grinding machine including a support; a carriage mounted thereon for oscillation with respect thereto, a work driving headstock supported on'the carriage for oscillation therewith, said headstock having a pattern cam receiving portion adapted to receive a pattern cam, a contact member carried by the support for operative engagement with the contact cam, means for resiliently oscillating the carriage in a direction to maintain a pattern cam in engagement with said contact member, driving means for rotating said headstock, a hydraulic rate controller for said driving means, including an adjustable rate a contact member carried by the support for oprative engagement with the contact cam, means for resiliently oscillating the carriage in a direction to maintain a pattern cam in engagement with said contact member, driving means for rotating said headstock, a hydraulic rate controller for said driving means including an adjustable rate valve carried by the support, means connecting the rate valve and the oscillatable carriage for varying the setting of the valve in accordance for removably securing said cartridges on the seats, said headstock mechanism having a pair of spaced axially aligned seating portions for selective mounting of work piece and pattern elements, said seating portions each having means for determining the rotative position of the element to be mounted thereon, and means intervening said position determining elements for varying their angularly phased relationship.

7. In a cam grinding machine, the combination with a base, of a carriage pivotally mounted on the base for oscillation with respect thereto, means for efiecting oscillatory movements of the carriage in accordance with the peripheral contour of the cam to be ground, means for supporting the cam to be ground on said oscillatory carriage, and means for determination of the rate of "presentation I of the ground to a grinding member, said means includsurface of the cam to be ROY G. KIRBY.

References Cited in the file of this patent 7 UNITED STATES PATENTS Number V Name Date 1,716,115 Clark et a1 June 4, 1929 1,938,439 Remington Dec. 5, 1933 2,018,847 Fraser Oct. 29, 1935 2,060,437 Harley Nov. 10, 1936 2,334,938 Lang Nov. 23, 1943 2,352,608 I Archer July 4, 1944 2,414,126 Sevin Jan. 14, 1947 2,415,801 Armitage et al Feb. 11, 1947 2,422,681 Johnson June 24, 1947 2,508,998 Green 1 May 23, 1950 2,557,043 7 -Wright et a1 June 12, 1951 FOREIGN PATENTS Number Country Date 12,235 GreatBritain May 26, 1913 

